How coronavirus lockdowns stopped flu in its tracks
▻https://www.nature.com/articles/d41586-020-01538-8
Lockdowns and social-distancing measures aimed at slowing the spread of coronavirus seem to have shortened the influenza season in the northern hemisphere by about six weeks.
Globally, an estimated 290,000–650,000 people typically die from seasonal flu, so a shorter flu season could mean tens of thousands of lives are spared. But the net impacts on global health will be hard to unpick against the large number of deaths from COVID-19 as well as other causes in 2020 and beyond. Tracking influenza and other infectious diseases can help to reveal the effectiveness of public-health policies aimed at stopping the coronavirus pandemic.
Seasonal flu cases in the northern hemisphere usually peak in February and tail off by the end of May. This year, unusually, lab-confirmed cases of influenza dropped precipitously in early April, a few weeks after the coronavirus pandemic was declared on 11 March (see ‘Flu season cut short by COVID-19 measures’). The data comes from tests of more than 150,000 samples from national influenza laboratories in 71 countries that report data to FluNet, a global surveillance system.
The early end to the flu season comes despite the fact that it started with a bang; in January, before the coronavirus pandemic, the influenza season was on track to be the most severe in decades.
There are other possible contributors to the decline: people with flu symptoms might have avoided clinics altogether, for example, isolating at home and so not showing up in the statistics. But the response to the pandemic is likely to be an important factor: “Public-health measures such as movement restrictions, social distancing and increased personal hygiene likely had an effect on decreasing influenza and other respiratory virus transmission,” said the World Health Organization in a statement to Nature.